Testosterone is necessary for normal sperm development. It activates genes in Sertoli cells, which promote differentiation of spermatogonia. It regulates acute HPA (hypothalamic–pituitary–adrenal axis) response under dominance challenge.[22] Androgen including testosterone enhances muscle growth. Testosterone also regulates the population of thromboxane A2 receptors on megakaryocytes and platelets and hence platelet aggregation in humans.[23][24]
Falling in love decreases men's testosterone levels while increasing women's testosterone levels. There has been speculation that these changes in testosterone result in the temporary reduction of differences in behavior between the sexes.[53] However, it is suggested that after the "honeymoon phase" ends—about four years into a relationship—this change in testosterone levels is no longer apparent.[53] Men who produce less testosterone are more likely to be in a relationship[54] or married,[55] and men who produce more testosterone are more likely to divorce;[55] however, causality cannot be determined in this correlation. Marriage or commitment could cause a decrease in testosterone levels.[56] Single men who have not had relationship experience have lower testosterone levels than single men with experience. It is suggested that these single men with prior experience are in a more competitive state than their non-experienced counterparts.[57] Married men who engage in bond-maintenance activities such as spending the day with their spouse/and or child have no different testosterone levels compared to times when they do not engage in such activities. Collectively, these results suggest that the presence of competitive activities rather than bond-maintenance activities are more relevant to changes in testosterone levels.[58]
Men who watch a sexually explicit movie have an average increase of 35% in testosterone, peaking at 60–90 minutes after the end of the film, but no increase is seen in men who watch sexually neutral films.[43] Men who watch sexually explicit films also report increased motivation, competitiveness, and decreased exhaustion.[44] A link has also been found between relaxation following sexual arousal and testosterone levels.[45]
Insulin causes lower Testosterone levels, so go easy on the carbs and eat more protein right? Well you need to be careful with protein consumption – Excess protein without fat can also cause insulin spikes. So go easy on that chicken breast with a side of egg white omelets washed down with a protein shake. From an insulin point of view you may as well drink a can of soda with some aminos acid! So what should you do? Eat more fat.
In addition to its role as a natural hormone, testosterone is used as a medication, for instance in the treatment of low testosterone levels in men and breast cancer in women.[10] Since testosterone levels decrease as men age, testosterone is sometimes used in older men to counteract this deficiency. It is also used illicitly to enhance physique and performance, for instance in athletes.
If you do take DAA I recommend cycling it (i.e. 5 days on, 2 off, over 4 weeks then 4 weeks off). And taking it with an aromatase inhibitor (which ensures the aspartic acid doesn’t get converted to estrogen). Especially as more studies are coming out showing the increase in testosterone is limited to a week or two before it drops back to normal levels.
In summary it’s important to know that this topic is still hotly debated, and there are a lot of inconsistencies in the data. We do know that soy contains phytoestrogens and does seem to have a lot of affects on the body, including some studies that show decreased Testosterone levels. For that reason (and the fact that it tastes like ass) I avoid it, and I recommend you also avoid it (in particular soy isolates!) if you’re seeking higher testosterone.
Clinical trials of the effect of testosterone on glucose metabolism in men have occurred in diabetic and non-diabetic populations. Data specific to aging males is not available. A series of studies investigated the effects of testosterone or dihydrotestosterone given for 6 weeks or 3 months to middle aged, non-diabetic obese men (Marin, Holmang et al 1992; Marin, Krotkiewski et al 1992; Marin et al 1993). It was found that physiological treatment doses led to improved insulin resistance, as measured by the gold standard technique using a euglycemic clamp and/or serum glucose and insulin responses during glucose tolerance test. These improvements were associated with decreased central obesity, measured by computered tomography (CT) or waist-hip ratio, without reduced total fat mass. Insulin resistance improved more with testosterone than dihydrotestosterone treatment and beneficial effects were greater in men with lower baseline testosterone levels. Increasing testosterone levels into the supraphysiological range lead to decreased glucose tolerance.
Common side effects from testosterone medication include acne, swelling, and breast enlargement in males.[10] Serious side effects may include liver toxicity, heart disease, and behavioral changes.[10] Women and children who are exposed may develop virilization.[10] It is recommended that individuals with prostate cancer not use the medication.[10] It can cause harm if used during pregnancy or breastfeeding.[10]

Testosterone is everywhere playing multiple roles from intrauterine life to advanced age. Table 1, the contents of which are always undergoing change primarily because of newly observed associations, provides an overview of the bodily systemic functions and patho-physiological states in which testosterone finds itself implicated. In some of these states there is a clear physiological cause and effect relationship. In others, evidence of the physiological role is early or tenuous.

This causes your body to burn fat for the next 36 hours to replace your body’s vital energy stores. It addition to increasing your T-levels, it can help burn between 3–9 times more fat, lower your resting heart rate, lower blood pressure, keep your brain young by increasing circulation, and aids in detoxification by stimulating the lymphatic system.
Cross-sectional studies conducted at the time of diagnosis of BPH have failed to show consistent differences in testosterone levels between patients and controls. A prospective study also failed to demonstrate a correlation between testosterone and the development of BPH (Gann et al 1995). Clinical trials have shown that testosterone treatment of hypogonadal men does cause growth of the prostate, but only to the size seen in normal men, and also causes a small increase in prostate specific antigen (PSA) within the normal range (Rhoden and Morgentaler 2005). Despite growth of the prostate a number of studies have failed to detect any adverse effects on symptoms of urinary obstruction or physiological measurements such as flow rates and residual volumes (Snyder et al 1999; Kenny et al 2000, 2001). Despite the lack of evidence linking symptoms of BPH to testosterone treatment, it remains important to monitor for any new or deteriorating problems when commencing patients on testosterone treatment, as the small growth of prostate tissue may adversely affect a certain subset of individuals.
The effects of testosterone in humans and other vertebrates occur by way of multiple mechanisms: by activation of the androgen receptor (directly or as DHT), and by conversion to estradiol and activation of certain estrogen receptors.[109][110] Androgens such as testosterone have also been found to bind to and activate membrane androgen receptors.[111][112][113]
Cardiovascular disease, and its underlying pathological process atherosclerosis, is an important cause of morbidity and mortality in the developed and developing world. Coronary heart disease in particular is the commonest cause of death worldwide (AHA 2002; MacKay and Mensah 2004). As well as increasing with age, this disease is more common in the male versus female population internationally, which has led to interest in the potential role of sex hormones in modulating risk of development of atherosclerosis. Concerns about the potential adverse effects of testosterone treatment on cardiovascular disease have previously contributed to caution in prescribing testosterone to those who have, or who are at risk of, cardiovascular disease. Contrary to fears of the potential adverse effects of testosterone on cardiovascular disease, there are over forty epidemiological studies which have examined the relationship of testosterone levels to the presence or development of coronary heart disease, and none have shown a positive correlation. Many of these studies have found the presence of coronary heart disease to be associated with low testosterone levels (Reviews: Jones, Jones et al 2003; Jones et al 2005).
Early infancy androgen effects are the least understood. In the first weeks of life for male infants, testosterone levels rise. The levels remain in a pubertal range for a few months, but usually reach the barely detectable levels of childhood by 4–7 months of age.[15][16] The function of this rise in humans is unknown. It has been theorized that brain masculinization is occurring since no significant changes have been identified in other parts of the body.[17] The male brain is masculinized by the aromatization of testosterone into estrogen, which crosses the blood–brain barrier and enters the male brain, whereas female fetuses have α-fetoprotein, which binds the estrogen so that female brains are not affected.[18]
In males, the testosterone test can help find the reason for sexual problems, like reduced sex drive or erectile dysfunction. If you’re having a hard time getting your partner pregnant, the test can tell if your blood testosterone level is low. It can also screen for problems with the hypothalamus or pituitary gland. This controls how much testosterone your body makes.

The production of the stress hormone cortisol blocks the production and effects of testosterone. From a biological perspective, cortisol increases your “fight or flight” response, thereby lowering testosterone-associated functions such as mating, competing, and aggression. Chronic stress can take a toll on testosterone production, as well as your overall health. Therefore, stress management is equally important to a healthy diet and regular exercise. Tools you can use to stay stress-free include prayer, meditation, laughter, and yoga. Relaxation skills, such as deep breathing and visualization, can also promote your emotional health.

It seems that adequate testosterone levels are an important influence on sexual symptoms in the aging male and also influence the response of men to PDE-5 inhibitors, the first line treatment for erectile dysfunction in men. Many would now suggest screening for testosterone deficiency in all men presenting with erectile dysfunction (Gore and Rajfer 2004; Shabsigh 2005). This would seem appropriate because, in addition to benefits on sexual function, identification and treatment of hypogonadal men with testosterone could improve other symptoms of hypogonadism and protect against other conditions such as osteoporosis.
If you are serious about losing weight, you have got to strictly limit the amount of processed sugar in your diet, as evidence is mounting that excess sugar, and fructose in particular, is the primary driving factor in the obesity epidemic. So cutting soda from your diet is essential, as is limiting fructose found in processed foods, fruit juice, excessive fruit and so-called "healthy" sweeteners like agave.
Many clinical studies have looked at the effect of testosterone treatment on body composition in hypogonadal men or men with borderline low testosterone levels. Some of these studies specifically examine these changes in older men (Tenover 1992; Morley et al 1993; Urban et al 1995; Sih et al 1997; Snyder et al 1999; Kenny et al 2001; Ferrando et al 2002; Steidle et al 2003; Page et al 2005). The data from studies, on patients from all age groups, are consistent in showing an increase in fat free mass and decrease in fat mass or visceral adiposity with testosterone treatment. A recent meta-analysis of 16 randomized controlled trials of testosterone treatment effects on body composition confirms this pattern (Isidori et al 2005). There have been less consistent results with regard to the effects of testosterone treatment of muscle strength. Some studies have shown an increase in muscle strength (Ferrando et al 2002; Page et al 2005) with testosterone whilst others have not (Snyder et al 1999). Within the same trial some muscle group strengths may improve whilst others do not (Ly et al 2001). It is likely that the differences are partly due to the methodological variations in assessing strength, but it also possible that testosterone has different effects on the various muscle groups. The meta-analysis found trends toward significant improvements in dominant knee and hand grip strength only (Isidori et al 2005).
Finally, we looked at the proprietary blends of our remaining boosters, and dug into their ingredient lists. Supplements frequently include ingredients known for their “folk-lore” value; they’re believed to work, even when there isn’t any scientific background to prove it. Though we didn’t ding points if an ingredient wasn’t proven to be good (just so long as it wasn’t proven to be bad), we didn’t want to include any ingredient with evidence of causing harm.
Zaima, N., Kinoshita, S., Hieda, N., Kugo, H., Narisawa, K., Yamamoto, A., ... Moriyama, T. (2016, September). Effect of dietary fish oil on mouse testosterone level and the distribution of eicosapentaenoic acid-containing phosphatidylcholine in testicular interstitium. Biochemistry and Biophysics Reports, 7, 259–265. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5613343/
We start with plastic. A lot of plastic contains bisphenol A (BPA); BPA is a weak synthetic estrogen. Like many other chemicals used in making plastics, BPA is a hormone disruptor and can block or mimic hormones and how they act in the body (34). If you think you’re safe with BPA plastic, think again. Research shows that BPA free plastic has similar estrogen-like effects on the body.

A large number of trials have demonstrated a positive effect of testosterone treatment on bone mineral density (Katznelson et al 1996; Behre et al 1997; Leifke et al 1998; Snyder et al 2000; Zacharin et al 2003; Wang, Cunningham et al 2004; Aminorroaya et al 2005; Benito et al 2005) and bone architecture (Benito et al 2005). These effects are often more impressive in longer trials, which have shown that adequate replacement will lead to near normal bone density but that the full effects may take two years or more (Snyder et al 2000; Wang, Cunningham et al 2004; Aminorroaya et al 2005). Three randomized placebo-controlled trials of testosterone treatment in aging males have been conducted (Snyder et al 1999; Kenny et al 2001; Amory et al 2004). One of these studies concerned men with a mean age of 71 years with two serum testosterone levels less than 12.1nmol/l. After 36 months of intramuscular testosterone treatment or placebo, there were significant increases in vertebral and hip bone mineral density. In this study, there was also a significant decrease in the bone resorption marker urinary deoxypyridinoline with testosterone treatment (Amory et al 2004). The second study contained men with low bioavailable testosterone levels and an average age of 76 years. Testosterone treatment in the form of transdermal patches was given for 1 year. During this trial there was a significant preservation of hip bone mineral density with testosterone treatment but testosterone had no effect on bone mineral density at other sites including the vertebrae. There were no significant alterations in bone turnover markers during testosterone treatment (Kenny et al 2001). The remaining study contained men of average age 73 years. Men were eligible for the study if their serum total testosterone levels were less than 16.5 nmol/L, meaning that the study contained men who would usually be considered eugonadal. The beneficial effects of testosterone on bone density were confined to the men who had lower serum testosterone levels at baseline and were seen only in the vertebrae. There were no significant changes in bone turnover markers. Testosterone in the trial was given via scrotal patches for a 36 month duration (Snyder et al 1999). A recent meta-analysis of the effects on bone density of testosterone treatment in men included data from these studies and two other randomized controlled trials. The findings were that testosterone produces a significant increase of 2.7% in the bone mineral density at the lumber spine but no overall change at the hip (Isidori et al 2005). These results from randomized controlled trials in aging men show much smaller benefits of testosterone treatment on bone density than have been seen in other trials. This could be due to the trials including patients who are not hypogonadal and being too short to allow for the maximal effects of testosterone. The meta-analysis also assessed the data concerning changes of bone formation and resorption markers during testosterone treatment. There was a significant decrease in bone resorption markers but no change in markers of bone formation suggesting that reduction of bone resorption may be the primary mode of action of testosterone in improving bone density (Isidori et al 2005).

A previous meta-analysis has confirmed that treatment of hypogonadal patients with testosterone improves erections compared to placebo (Jain et al 2000). A number of studies have investigated the effect of testosterone levels on erectile dysfunction in normal young men by inducing a hypogonadal state, for example by using a GnRH analogue, and then replacing testosterone at varying doses to produce levels ranging from low-normal to high (Buena et al 1993; Hirshkowitz et al 1997). These studies have shown no significant effects of testosterone on erectile function. These findings contrast with a similar study conducted in healthy men aged 60–75, showing that free testosterone levels achieved with treatment during the study correlate with overall sexual function, including morning erections, spontaneous erections and libido (Gray et al 2005). This suggests that the men in this older age group are particularly likely to suffer sexual symptoms if their testosterone is low. Furthermore, the severity of erectile dysfunction positively correlates with lower testosterone levels in men with type 2 diabetes (Kapoor, Clarke et al 2007).
The mineral zinc is important for testosterone production, and supplementing your diet for as little as six weeks has been shown to cause a marked improvement in testosterone among men with low levels.1 Likewise, research has shown that restricting dietary sources of zinc leads to a significant decrease in testosterone, while zinc supplementation increases it2 -- and even protects men from exercised-induced reductions in testosterone levels.3
Intramuscular testosterone injections were first used around fifty years ago. Commercially available preparations contain testosterone esters in an oily vehicle. Esterification is designed to retard the release of testosterone from the depot site into the blood because the half life of unmodified testosterone would be very short. For many years intramuscular preparations were the most commonly used testosterone therapy and this is still the case in some centers. Pain can occur at injection sites, but the injections are generally well tolerated and free of major side effects. Until recently, the available intramuscular injections were designed for use at a frequency of between weekly and once every four weeks. These preparations are the cheapest mode of testosterone treatment available, but often cause supraphysiological testosterone levels in the days immediately following injection and/or low trough levels prior to the next injection during which time the symptoms of hypogonadism may return (Nieschlag et al 1976). More recently, a commercial preparation of testosterone undecanoate for intramuscular injection has become available. This has a much longer half life and produces testosterone levels in the physiological range throughout each treatment cycle (Schubert et al 2004). The usual dose frequency is once every three months. This is much more convenient for patients but does not allow prompt cessation of treatment if a contraindication to testosterone develops. The most common example of this would be prostate cancer and it has therefore been suggested that shorter acting testosterone preparations should preferably used for treating older patients (Nieschlag et al 2005). Similar considerations apply to the use of subcutaneous implants which take the form of cylindrical pellets injected under the skin of the abdominal wall and steadily release testosterone to provide physiological testosterone levels for up to six months. Problems also include pellet extrusion and infection (Handelsman et al 1997).
All the active substances available in TestoGen are fully natural. And their efficacy and safety is science-backed. So, if you don’t have individual sensitivity to the supplement ingredients and purchase the product directly from the manufacturer instead of purchasing from unknown suppliers, the likelihood of side effects during the supplementation is minimal. And the customer feedback proves this.
In contrast to steroids, testosterone boosters have a fully different mechanism of action. They are the products which contain the natural ingredients only. These ingredients act by stimulating the man’s body to synthesize own testosterone. So, testosterone levels grow naturally without negative health effects associated with the intake of steroids.
If a man's testosterone looks below the normal range, there is a good chance he could end up on hormone supplements—often indefinitely. "There is a bit of a testosterone trap," Dr. Pallais says. "Men get started on testosterone replacement and they feel better, but then it's hard to come off of it. On treatment, the body stops making testosterone. Men can often feel a big difference when they stop therapy because their body's testosterone production has not yet recovered."